The present invention relates to material compositions that include ceramic material, and to methods, systems, devices, and articles involving such compositions, more particularly such compositions that are relatively low in density and are otherwise suitable for use in personnel/personal ballistic armor applications.
Current military armor applications include manned land vehicles, manned air vehicles (e.g., aircraft and rotorcraft), stationary structures, and persons. Other applications of armor systems are less common but may become more prevalent in the future, including unmanned air vehicles, manned marine vehicles (e.g., ships), unmanned marine vehicles, and missiles.
Various armor constructions and configurations have been disclosed involving utilization of ceramic material. See, e.g., the following U.S. patents, each of which is incorporated herein by reference: Cohen, U.S. Pat. No. 7,383,762 B2, issued 10 Jun. 2008, entitled “Ceramic Pellets and Composite Armor Panel Containing the Same”; Aghajanian et al., U.S. Pat. No. 7,332,221 B2, issued 12 Sep. 2008, entitled “Boron Carbide Composite Bodies, and Methods for Making Same”; Raichel et al., U.S. Pat. No. 7,284,469 B2, issued 23 Oct. 2007, entitled “Protection from Kinetic Threats Using Glass-Ceramic Material”; Breslin et al., U.S. Pat. No. 7,267,882 B2, issued 11 Sep. 2007, entitled “Ceramic/Metal Material and Method for Making Same”; Benitsch U.S. Pat. No. 7,128,963 B2, issued 31 Oct. 2006, entitled “Ceramic Composite Body, Method for Fabricating Ceramic Composite Bodies, and Armor Using Ceramic Composite Bodies”; Aghajanian et al. U.S. Pat. No. 7,104,177 B1 issued 12 Sep. 2006, entitled “Ceramic-Rich Composite Armor, and Methods for Making Same”; deWitt, U.S. Pat. No. 7,067,031 B2, issued 27 Jun. 2006, entitled “Process for Making A Ceramic Armor Plate”; Rettenbacher et al., U.S. Pat. No. 7,026,045 B2, issued 11 Apr. 2006, entitled “Multilayer Composite Armour”; Cohen, U.S. Pat. No. 6,860,186 B2, issued 1 Mar. 2005, entitled “Ceramic Bodies and Ballistic Armor Incorporating the Same”; Mohr et al., U.S. Pat. No. 6,792,843 B2, issued 21 Sep. 2004, entitled “Armor-Plating Composite”; McCormick et al., U.S. Pat. No. 6,609,452 B1, issued 26 Aug. 2003, entitled “Silicon Carbide Armor Bodies, and Methods for Making Same”; Ghiorse et al., U.S. Pat. No. 6,601,497 B2, issued 5 Aug. 2003, entitled “Armor with In-Plane Confinement of Ceramic Tiles”; Shih et al., U.S. Pat. No. 6,532,857 B1, issued 18 Mar. 2003, entitled “Ceramic Array Armor”; Lyons, U.S. Pat. No. 6,332,390 B1, issued 25 Dec. 2001, entitled “Ceramic Tile Armor with Enhanced Joint and Edge Protection”; Lyons et al., U.S. Pat. No. 6,253,655 B1, issued 3 Jul. 2001, entitled “Lightweight Armor with a Durable Spall Cover”; Lyons, U.S. Pat. No. 6,009,789, issued 4 Jan. 2000, entitled “Ceramic Tile Armor with Enhanced Joint and Edge Protection.”
Ceramic materials that are particularly known in the art to be suitable for use in armor applications include aluminum oxide (commonly called “alumina”), silicon carbide, boron carbide, and titanium carbide. These conventional armor ceramics have been developed over the last thirty years or so, represent the current state of the art, and have been relied upon in conventional practice of armor systems—for instance, for protection against impact by a projectile such as a ballistic body (e.g., small arms fire) or an explosive fragment (e.g., shrapnel from a bomb blast). Although conventional ceramic armor materials often perform satisfactorily, they (and therefore armor systems implementing them) tend to be expensive to produce. Furthermore, conventional ceramic armor materials sometimes fail, or perform less than optimally, when impacted by a projectile. Generally speaking, there is a recognized and continuing need in the armor-related arts to improve the capabilities of materials to withstand significant impacts.
The weight of an armor system tends to be more critical in the realm of personnel/personal armor, such as helmets and body armor. Through the years, military helmets have evolved from the metal (e.g., steel) helmets of the First and Second World Wars, to plastic helmets, to the current state-of-the-art composite helmets. U.S. ground troops are currently outfitted with a polymer composite helmet including aramid fibers that is capable of stopping handgun threats but is incapable of stopping greater projectile threats, such as rifles and other more powerful firearms. Body armor members (e.g., plates) made of ceramic, metal (e.g., steel or titanium), or polyethylene have seen development for use by military and law enforcement. In particular, body armor systems employing one or more ceramic inserts have recently seen military use, and have demonstrated varying degrees of imperviousness to greater projectile threats, but these body armor systems have been criticized for imposing excessive weight upon the wearer. In addition, modern-day personnel/personal armor systems have generally been expensive to mass-produce.
In theory, a ballistic helmet or vest made of a ceramic material could provide greater resistance to projectile impact than what is currently used. In practice, however, items such as helmets and vests represent especially difficult applications for ceramic armor because of both weight restrictions and specialized shapes. Ceramic armor materials of more advanced capabilities are most often prepared by hot-pressing (pressure-assisted sintering), a technique that is not suitable for preparation of an article of complex shape, such as a helmet or a vest; in general, hot-pressing is limited in terms of reduced production capacity and higher production cost.
Accordingly, in the realm of personnel/personal armor, the need exists for materials and systems that are practical and economical for extensive manufacture, are sufficiently lightweight, and afford more effective ballistic protection than current versions.